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<h1>BK7 optical glass</h1>

BK7 is a widely used optical glass known for its high transmission and clear, colorless appearance. Composed primarily of silica and boron oxide, BK7 is popular in a broad range of optical applications, including lenses, prisms, and windows. It exhibits good mechanical properties and can be easily polished to a high optical quality. While it is not as resistant to thermal shock or chemical corrosion as some specialized glasses like borosilicate or fused silica, it is considerably less expensive, making it a cost-effective choice for many applications. Its relatively high refractive index and low dispersion make it suitable for a variety of optical systems, particularly those operating in the visible spectrum. Because of its versatility and cost-effectiveness, BK7 is often considered the "go-to" material for general-purpose optical components.

<h2>Analogs of BK7 glass produced by different makers</h2>
<table>
<tr>
<th>Maker</th>
<th>Glass</th>
</tr>
<tr>
<td>SCHOTT</td>
<td>N-BK7</td>
</tr>
<tr>
<td>OHARA</td>
<td>S-BSL7</td>
</tr>
<tr>
<td>HIKARI</td>
<td>J-BK7A</td>
</tr>
<tr>
<td>CDGM</td>
<td>H-K9L</td>
</tr>
<tr>
<td>HOYA</td>
<td>BSC7</td>
</tr>
<tr>
<td>SUMITA</td>
<td>K-BK7</td>
</tr>
<tr>
<td>LZOS</td>
<td>K8</td>
</tr>
</table>

<h2>External links</h2>
<ul>
<li><a href="https://en.wikipedia.org/wiki/Crown_glass_(optics)">Crown glass - Wikipedia</a></li>
</ul>
